A subterranean formation or zone may serve as a source for a natural resource such as oil, gas, or water. To produce such a natural resource from the subterranean formation, a wellbore may be drilled into the subterranean formation. Where the subterranean formation from which the natural resource is to be produced lies beneath a body of water, a tubular (e.g., a conductor) may extend from the surface or near the surface of the body of water through the body of water to a depth within the wellbore. The annular space between the tubular and the wellbore may be cemented, thereby securing the tubular to the wellbore and isolating the various production zones within the wellbore. The tubular may comprise multiple concentric strings of pipe and the annular space between the concentric pipe strings may be cemented, thus providing a conduit for the communication of fluids produced from the subterranean formation.
When a wellbore has reached the end of its useful life, becomes unproductive, is damaged, or is otherwise no longer desirable to operate, an operator may choose to abandon the wellbore. Before the wellbore may be abandoned, it must be decommissioned. Where a tubular, such as a conductor, rises through a body of water, various decommissioning regulations generally dictate that the tubular be removed from the water.
Removal of the tubular is often a difficult, time-consuming, and expensive under-taking, often due in some part to the weight of the tubular that must be removed from the water. This is particularly true in a scenario where the tubular comprises multiple concentric pipes with cement filling the space between those pipes or where the tubular extends a great depth, sometimes hundreds, thousands, or even tens of thousands of feet below the surface of the body of water. Conventionally, removal of the tubular has been accomplished via the use of cranes, hoists, and the like, often located on the platform or on other surface vessels. However, the weight of the tubular may approach or exceed the lifting/load capacity of the cranes, hoists, platform, or support vessels. Thus, conventionally, it may be necessary to cooperatively use several cranes located on multiple surface vessels or platforms to achieve the necessary lifting capacity, making removal of the tubular difficult, expensive, and time-consuming. Therefore, a need exists for improved systems and methods for decommissioning wellbores.